package org.jeecg.common.util;

public class UnitUtil {

    public static Integer calculate2PointDistance(double centerLat, double centerLng, double targetLat, double targetLng) {
        return (int) GetDistance(centerLng, centerLat, targetLng, targetLat);
    }

//    public static void main(String[] args) {
//        System.out.println(calculate2PointDistance(26.615183, 106.649612, 26.559322, 106.674735));
//    }

    /**
     * 默认地球半径
     */
    private static double EARTH_RADIUS = 6378137;//赤道半径(单位m)

    /**
     * 转化为弧度(rad)
     */

    private static double rad(double d) {
        return d * Math.PI / 180.0;
    }

    /**
     * @param lon1 第一点的精度
     * @param lat1 第一点的纬度
     * @param lon2 第二点的精度
     * @param lat2 第二点的纬度
     * @return 返回的距离，单位m
     */

    public static double GetDistance(double lon1, double lat1, double lon2, double lat2) {
        double radLat1 = rad(lat1);
        double radLat2 = rad(lat2);
        double a = radLat1 - radLat2;
        double b = rad(lon1) - rad(lon2);
        double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2) + Math.cos(radLat1) * Math.cos(radLat2) * Math.pow(Math.sin(b / 2), 2)));
        s = s * EARTH_RADIUS;
        s = Math.round(s * 10000) / 10000;
        return s;
    }
}
